Question

How many MOLES of chlorine are present in 4.85 grams of boron trichloride ?

Answer 1

The moles of Chlorine in 4.85 g BCl₃ is 0.1242 moles

Solution and Explanation:

• Boron trichloride is an inorganic compound containing one Boron atom and three chlorine atoms.

Step 1: Mass of Chlorine in 4.85 g BCl₃

• 1 mole of BCl₃ contains three atoms of Chlorine

• But, the molar mass of BCl₃ is 117.17 g/mol and the atomic mass of Chlorine is 35.45 g
• Therefore; 117.17 g BCl₃ contains 106.35 g (35.45 g ×3) chlorine.
• Hence; 4.85 g BCl₃ will contain;

`((4.85g)(106.35g))/(117.17 g)`

= 4.402 g Chlorine

Step 2: Moles of Chlorine in 4.85 g BCl₃

• Number of moles is given by mass divided by atomic mass

Therefore;

`Number of moles = (4.402 g)/(35.45g/mol)`

= 0.1242 moles

Hence; 4.85 g BCl₃ contains is 0.1242 moles Chlorine